Midi Parser in C#

A small midi parser written in C#. Just drop MidiFile.cs into your project and use it like:

var midiFile = new MidiFile("song.mid");

// 0 = single-track, 1 = multi-track, 2 = multi-pattern
var midiFileformat = midiFile.Format;

// also known as pulses per quarter note
var ticksPerQuarterNote = midiFile.TicksPerQuarterNote;

foreach(var track in midiFile.Tracks)
{
    foreach(var midiEvent in track.MidiEvents)
    {
        if(midiEvent.MidiEventType == MidiEventType.NoteOn)
        {
            var channel = midiEvent.Channel;
            var note = midiEvent.Note;
            var velocity = midiEvent.Velocity;
        }
    }

    foreach(var textEvent in track.TextEvents)
    {
        if(textEvent.TextEventType == TextEventType.Lyric)
        {
            var time = textEvent.Time;
            var text = textEvent.Value;
        }
    }    
}

Notes

• Extracts channel number from the event type for easier use.
• Provides easy access to events relevant to music performance like tempo and time signature.
• The code is easy to extend to support other event types.

Some implementation details:

• Events are stored without polymorphism using a small shared MidiEvent struct.
• Text events are stored separately because of their reference to strings.
• The parsing is done using byte arrays instead of streams since midi files are so small.
• Only works in one direction so it can't write midi files.

Some event types are preprocessed during the parsing:

• Note on events with zero velocity are normalized to note off events.
• Tempo events are simplified to beats per minute.
• Time signature events are simplified to standard notation.

Midi File

class MidiFile
{
    int Format;
    int TicksPerQuarterNote;
    MidiTrack[] Tracks;
}

class MidiTrack
{
    int Index;
    List<MidiEvent> MidiEvents;
    List<TextEvent> TextEvents;
}

Midi Events

struct MidiEvent
{
    int Time;
    byte Type;
    byte Arg1;
    byte Arg2;
    byte Arg3;
}

Type	Arg1	Arg2	Arg3
NoteOff	Channel	Note	Velocity
NoteOn	Channel	Note	Velocity
PitchBendChange	Channel	Value	Value
KeyAfterTouch	Channel	Note	Amount
ChannelAfterTouch	Channel	Amount	-
ProgramChange	Channel	Program	-
ControlChange	Channel	BankSelect	Value
	Channel	Modulation	Value
	Channel	Volume	Value
	Channel	Balance	Value
	Channel	Pan	Value
	Channel	Sustain	Value
MetaEvent	Tempo	BeatsMinute	-
	TimeSignature	Numerator	Denominator
	KeySignature	SharpsFlats	MajorMinor

Text Events

struct TextEvent
{
    int Time;
    byte Type;
    string Value;
}

Type
Text
TrackName
Lyric